Are New Yorkers healthier than the average American because they walk so much, exercise in parks and eat healthier foods? A Columbia study is examining the link between body size and New York City's built environment with the help of $1.6 million from the National Institutes of Health.

The project, led by Andrew Rundle, assistant professor of epidemiology at Columbia , is set to test the theory that various factors -- including good sidewalks and decent public transit, and the right mix of local food stores and restaurants -- can influence exercise and diet to the point of reducing obesity.

Rundle noted the importance of conducting this kind of micro-level study. "Urban policymakers need research generalizable to their locale if they are to make informed decisions about the costs and benefits of zoning, economic development, public transit and other matters that may shape physical activity," he explained.

Rundle's research team is gathering detailed information on land use, transportation networks, access to parks and other green space and the availability of grocery stores, restaurants, and other retail establishments, using a geographic information system ( GIS ) to link this information to health datasets for New York City and its surrounding suburbs.

The project is a joint effort among researchers from Columbia's Mailman School of Public Health and the Institute for Social and Economic Research and Policy (ISERP), as well as the University of Michigan, Mt. Sinai School of Medicine and Smith College.